Blowing device and vacuum cleaner

ABSTRACT

A blowing device includes a motor including a rotor rotatable, an impeller, a motor housing, a blower case, and stator blades including at least a first stator blade provided with a stator blade recess portion. A communication hole in the motor housing is provided in the first stator blade and is in communication with the stator blade recess portion. The first stator blade includes front and rear wall portions. Axial directions of the front and rear wall portions are longitudinal directions thereof. The communication hole is provided in the circumferential direction and between the front wall portion and the rear wall portion. The first stator blade includes a connection wall portion. An upper surface of the connection wall portion extends towards an axial direction lower side as the upper surface extends towards a radial direction inner side.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to Japanese Patent Application No. 2017-244948 filed on Dec. 21, 2017. The entire contents of this application are hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present disclosure relates to a blowing device and a vacuum cleaner provided with the same.

2. Description of the Related Art

Hitherto, a blowing device that includes a plurality of stator blades is known. The blowing device is mounted in a vacuum cleaner or the like. For example, in a known electric blower, air that has been suctioned through an intake port with a rotation of an impeller passes through the impeller, a diffuser, and an inside of a bracket while cooling a stator, a rotor, and the like and is ultimately discharged to a portion external to the electric blower.

However, in known electric blowers, air directly enters a bracket inner portion through the diffuser to cool the stator and the rotor. Accordingly, the air blowing efficiency of the electric blower is decreased.

SUMMARY OF THE INVENTION

A blowing device according to an exemplary embodiment of the present disclosure includes a motor including a rotor rotatable about a central axis extending in an up-down direction, an impeller that is fixed to the rotor and that is rotatable together with the rotor, a motor housing disposed on a radial direction outer side with respect to the motor, a blower case disposed on the radial direction outer side with respect to the motor housing, and a plurality of stator blades arranged in a circumferential direction and between the motor housing and the blower case. The plurality of stator blades include at least a single first stator blade provided with a stator blade recess portion recessed in a surface of the stator blade. A communication hole that connects an internal portion and an external portion of the motor housing to each other is provided in the motor housing. The communication hole is provided between a forward rotation direction end portion and a backward rotation direction end portion in the first stator blade and is in communication with the stator blade recess portion. The first stator blade includes a front wall portion disposed in the forward rotation direction end portion, and a rear wall portion disposed in the backward rotation direction end portion. An axial direction of each of the front wall portion and the rear wall portion is a longitudinal direction. The communication hole is provided in the circumferential direction and between the front wall portion and the rear wall portion. The first stator blade further includes a connection wall portion that connects a lower end portion of the front wall portion and a lower end portion of the rear wall portion to each other. An upper surface of the connection wall portion extends towards an axial direction lower side as the upper surface extends towards a radial direction inner side.

The above and other elements, features, steps, characteristics and advantages of the present disclosure will become more apparent from the following detailed description of the preferred embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an external view of a blowing device.

FIG. 2 is a longitudinal section illustrating a configuration example of the blowing device.

FIG. 3A is an enlarged view illustrating an example of a first stator blade.

FIG. 3B is a cross-sectional view of a vicinity of the first stator blade viewed in a circumferential direction.

FIG. 3C is a cross-sectional view of a vicinity of the first stator blade viewed from an axial direction upper side.

FIG. 4 is an enlarged view illustrating a first stator blade according to a first modification.

FIG. 5 is an enlarged view illustrating a first stator blade according to a second modification.

FIG. 6 is an enlarged view illustrating a first stator blade according to a third modification.

FIG. 7 is an example of a vacuum cleaner in which the blowing device is mounted.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, an exemplary embodiment of the present disclosure will be described with reference to the drawings. Note that in the present specification, a rotation axis of a motor 110 of a blowing device 100 is referred to as a “central axis CA”, and a direction parallel to the central axis CA is referred to as an “axial direction”. A direction oriented in the axial direction from a substrate 6 described later towards an impeller 120 described later is referred to as an “axial direction upper side” that is a first side in the axial direction, and a direction oriented in the axial direction from the impeller 120 towards the substrate 6 is referred to as an “axial direction lower side” that is a second side in the axial direction. In each of the components, an end portion on the axial direction upper side is referred to as an “upper end portion”, and an end position on the axial direction upper side is referred to as an “upper end”. In each of the components, an end portion on the axial direction lower side is referred to as a “lower end portion”, and an end position on the axial direction lower side is referred to as a “lower end”. Furthermore, among the surfaces of the components, a surface oriented towards the axial direction upper side is referred to as an “upper surface”, and a surface oriented towards the axial direction lower side is referred to as an “undersurface”.

A direction orthogonal to the central axis CA is referred to as a “radial direction”. A direction in the radial direction oriented towards the central axis CA is referred to as a “radial direction inner side” and a direction in the radial direction distancing away from the central axis CA is referred to as a “radial direction outer side”. In each of the components, an end portion on the radial direction inner side is referred to as a “radial direction inner end portion”, and an end position on the radial direction inner side is referred to as a “radial direction inner end”. In each of the components, an end portion on the radial direction outer side is referred to as a “radial direction outer end portion”, and an end position on the radial direction outer side is referred to as a “radial direction outer end”. Furthermore, in the lateral surface of each component, a lateral surface oriented towards the radial direction inner side is referred to as a “radial direction inner lateral surface”, and a lateral surface oriented towards the radial direction outer side is referred to as a “radial direction outer lateral surface”.

A rotation direction of a rotor 1 about the central axis CA may be referred to as a “circumferential direction”. Furthermore, a direction in which the rotor 1 moves forward in the circumferential direction is referred to as a “forward rotation direction FRD”, and a direction in which the rotor 1 moves backwards in the circumferential direction is referred to as a “backward rotation direction BRD”. In other words, the “backward rotation direction BRD” is a direction opposite to the “forward rotation direction FRD”. In each of the components, an end portion in the forward rotation direction FRD is referred to as a “forward rotation direction end portion” and an end position in the forward rotation direction FRD is referred to as a “rotation direction front end”. Furthermore, in each of the components, an end portion in the backward rotation direction BRD is referred to as a “backward rotation direction end portion”, and an end position in the backward rotation direction BRD is referred to as a “rotation direction back end”.

Note that the names of the directions, the end portions, and the surfaces described above do not illustrate the actual positional relationships and directions when installed in a piece of equipment.

The blowing device 100 according to an exemplary embodiment of the present disclosure will be described first. FIG. 1 is an external view of the blowing device 100. FIG. 2 is a longitudinal section illustrating a configuration example of the blowing device 100. Note that in order to facilitate understanding of the configuration, a blower case 32 described later is depicted in a transparent manner in FIG. 1. FIG. 2 illustrates a cross section structure in which the blowing device 100 is imaginarily cut along a plane including the central axis CA.

The blowing device 100 includes the motor 110, the impeller 120, and a casing 3. The impeller 120 is a vanes wheel including a plurality of vanes 121 capable of rotating about the central axis CA. The impeller 120 is provided at an upper portion of the motor 110. The impeller 120 is capable of rotating about the central axis that extends in an up-down direction. The casing 3 houses at least a portion of the motor 110 and at least a portion of the impeller 120.

The motor 110 is of an inner rotor type and drives and rotates the impeller 120. The motor 110 includes the rotor 1, a stator 2, a bracket 4, and the substrate 6.

The rotor 1 is rotatable about the central axis CA extending in the up-down direction. In other words, the motor 110 includes the rotor 1 rotatable about the central axis CA that extends in the up-down direction. The rotor 1 includes a shaft 10, a magnet 11, and a holding member 12. The shaft 10 is a rotating shaft that extends upwards and downwards in the axial direction. The impeller 120 is attached to the upper portion of the shaft 10. In other words, the impeller 120 is fixed to the rotor 1 and is rotatable together with the rotor 1. Furthermore, the vanes 121 are rotatable in the rotation direction of the rotor 1. The magnet 11 has a tubular shape extending in the axial direction and is fixed to a radial direction outer lateral surface of the shaft 10. The holding member 12 is fixed to a radial direction outer lateral surface of the magnet 11. The holding member 12 is disposed on the radial direction inner side with respect to the stator 2 and opposes the stator 2 in the radial direction.

The motor 110 further includes the stator 2 disposed on a radial direction outer side of the rotor 1. The stator 2 is rotated by driving the rotor 1. The stator 2 includes a stator core 21, an insulator 22, and a plurality of coil portions 23. In other words, the stator 2 includes the stator core 21 provided with the coil portions 23. The stator core 21 is formed of laminated steel plates that are electromagnetic steel plates laminated in the axial direction, for example, and is fixed to the casing 3. More specifically, the stator core 21 includes a core back 21C and teeth 21T. The core back 21C has an annular shape surrounding the central axis CA. Not that an “annular shape” herein includes, in addition to a case in which the entire circumstance is continuously connected, a case in which a portion of the circumstance is discontinuous. Furthermore, “the core back 21C having an annular shape” includes a case in which there are a plurality of core backs 21C and in which the plurality of core backs 21C are arranged in the circumferential direction. In the present embodiment, a portion of a radial direction outer end portion of the core back 21C is fixed to a radial direction inner lateral surface of a cylindrical portion 312. The cylindrical portion 312 is a portion of a motor housing 31 (described later) in the casing 3. The teeth 21T each extend in the radial direction from the core back 21C towards the holding member 12. The insulator 22 is, for example, an insulating member formed using a resin material and covers at least a portion of the stator core 21, in particular, covers the teeth 21T. The coil portions 23 are winding members formed of conducting wires wound around the teeth 21T of the stator core 21 with the insulator 22 in between. In other words, the stator core 21 and the coil portions 23 are electrically insulated from each other with the insulator 22. Furthermore, the plurality of coil portions 23 are arranged in the circumferential direction around the shaft 10.

The bracket 4 includes a lower bearing holder 41 and a lid portion 42. The lower bearing holder 41 rotatably supports the shaft 10 with a lower bearing 41 a interposed therebetween. Furthermore, the lower bearing holder 41 has a tubular shape extending in the axial direction. The lower bearing 41 a is disposed on a radial direction inner lateral surface of the lower bearing holder 41. The shaft 10 is inserted through both the lower bearing 41 a and the lower bearing holder 41. Although not limited to any bearing in particular, a ball bearing, a sleeve bearing, or the like can be used as the lower bearing 41 a. The lid portion 42 extends towards the radial direction outer side from a lower end portion of the lower bearing holder 41 and covers an opening at a lower end portion of the casing 3.

In the present embodiment, the substrate 6 is disposed below the bracket 4 in the axial direction and is fixed to the lid portion 42. The substrate 6 is a plate-shaped circuit substrate and is formed of a resin material such as an epoxy resin. The substrate 6 is electrically connected to the coil portions 23. The substrate 6 is electrically connected to a device and the like external to the motor 110 through a connection line (not shown) that is drawn out to the outside of the motor 110. Furthermore, an electronic component 61 is mounted on the substrate 6. The electronic component 61 includes a power supply circuit and a control circuit of the motor 110.

The casing 3 includes the motor housing 31, the blower case 32, and a plurality of stator blades 33. In other words, the blowing device 100 includes the motor housing 31, the blower case 32, and the plurality of stator blades 33. The motor housing 31, the blower case 32, and the stator blades 33 constitute the same member in the present embodiment, in other words, the motor housing 31, the blower case 32, and the stator blades 33 are an integral structure. However, not limited to the above example, at least one of the above may be a separate member, in other words, the above do not have to be an integral structure.

The motor housing 31 houses at least a portion of the motor 110. In the present embodiment, the motor housing 31 houses the rotor 1 and the stator 2. The motor housing 31 has a tubular shape with a lid. The motor housing 31 includes an upper bearing holder 311 and the cylindrical portion 312.

The upper bearing holder 311 rotatably supports the shaft 10 with an upper bearing 311 a interposed therebetween. Furthermore, the upper bearing holder 311 extends in the radial direction. The upper bearing holder 311 is, at the center, provided with a through hole 311 b that penetrates thereof in the axial direction. The upper bearing 311 a is disposed on an inner lateral surface of the through hole 311 b. The shaft 10 is inserted through both the upper bearing 311 a and the through hole 311 b. Although not limited to any bearing in particular, a ball bearing, a sleeve bearing, or the like can be used as the upper bearing 311 a.

The cylindrical portion 312 extends downwards in the axial direction from a radial direction outer end portion of the upper bearing holder 311. The cylindrical portion 312 is disposed on the radial direction outer side with respect to the motor 110. In other words, the motor housing 31 is disposed on the radial direction outer side with respect to the motor 110. Communication holes 3 a are provided in the motor housing 31. In more detail, the communication holes 3 a are provided in the cylindrical portion 312. The communication holes 3 a penetrate the cylindrical portion 312 of the motor housing 31 in the radial direction. In other words, the communication holes 3 a connects an internal portion and an outer portion of the motor housing 31 to each other. By providing the communication holes 3 a in the motor housing 31, the portion internal to the motor 110 can be cooled with the airflow flowing from the portion external to the portion internal to the motor housing 31 through the communication holes 3 a. The arrangement of the communication holes 3 a is not limited to any arrangement in particular. In the present embodiment, the communication holes 3 a are provided in a plural number and at equal distances in the circumferential direction. With the above configuration, since the communication holes 3 a are disposed at equal distances in the circumferential direction, the motor 110 can be cooled evenly in the circumferential direction.

The blower case 32 houses the impeller 120. The blower case 32 is disposed on a radial direction outer side of the motor housing 31. An intake port 32 a is provided at an upper end portion of the blower case 32. The blower case 32 forms a gap with the motor housing 31. The gap is a distribution passage of the airflow generated by the rotation of the impeller 120. A ventilation port 32 b is provided at a lower end portion of the blower case 32 and between a radial direction outer lateral surface of the motor housing 31. The air drawn in through the intake port 32 a with the rotation of the impeller 120 flows downwards in the axial direction through a portion between the motor housing 31 and the blower case 32 and is sent out to a portion outside the casing 3 through the ventilation port 32 b. Note that a portion of the airflow flowing between the motor housing 31 and the blower case 32 flows into the motor housing 31 through the communication holes 3 a and is used to cool the stator 2 and the like. The configuration of the above will be described later.

The stator blades 33 are disposed between the motor housing 31 and the blower case 32 and are arranged in a plural number in the circumferential direction. The stator blades 33 are connection portions that connect the motor housing 31 and the blower case 32 to each other in the radial direction. Radial direction inner end portions of the stator blades 33 are connected to the radial direction outer lateral surface of the motor housing 31. Radial direction outer end portions of the stator blades 33 are connected to a radial direction inner lateral surface of the blower case 32.

Furthermore, the stator blades 33 each extend in the axial direction. As upper end portions of the stator blades 33 extend towards the axial direction upper side, the upper end portions curve towards the backward rotation direction BRD. Accordingly, the airflow generated by the rotation of the impeller 120 easily flows between adjacent stator blades 33 in the circumferential direction.

The plurality of stator blades 33 include at least a single first stator blade 7 in which a stator blade recess portion 7 a that is a recess in a surface of the stator blade 7 is provided. Hereinafter, among the plurality of stator blades 33, the stator blade 7 in which the stator blade recess portion 7 a is provided is referred to as the “first stator blade 7” and the stator blades 331 other than the first stator blade 7 are referred to as “second stator blades 331”. Note that a configuration of the first stator blade 7 will be described later.

The stator blade recess portion 7 a is formed between the forward rotation direction end portion and the backward rotation direction end portion of the first stator blade 7 in the upper portion of the first stator blade 7. Furthermore, when viewed in the radial direction, the communication hole 3 a is formed between the forward rotation direction end portion and the backward rotation direction end portion of the first stator blade 7. When viewed in the radial direction, the communication hole 3 a overlaps a portion of the stator blade recess portion 7 a and is in communication with the stator blade recess portion 7 a. In other words, the communication hole 3 a is provided between the forward rotation direction end portion and the backward rotation direction end portion in the first stator blade 7 and is in communication with the stator blade recess portion 7 a. With the above configuration, the airflow that is generated by the rotation of the impeller 120 and that flows into the stator blade recess portion 7 a passes through the communication hole 3 a and flows into the gap between the motor 110 and the motor housing 31 in a smooth manner. Accordingly, the motor 110 can be cooled without decreasing the air blowing efficiency.

The stator blade recess portion 7 a is not formed in each of the second stator blades 331. In the upper portion of each second stator blade 331, a forward rotation direction lateral surface and a backward rotation direction lateral surface curve in the backward rotation direction BRD as the upper portion extends towards the axial direction upper side. Furthermore, the forward rotation direction lateral surface is a curved surface protruding towards the axial direction upper side and in the forward rotation direction FRD. The backward rotation direction lateral surface is a curved surface recessed towards the axial direction upper side and in the forward rotation direction FRD.

A configuration of the first stator blade 7 will be described next. FIG. 3A is an enlarged view illustrating an example of the first stator blade 7. FIG. 3B is a cross-sectional view of a vicinity of the first stator blade 7 viewed in the circumferential direction. FIG. 3C is a cross-sectional view of a vicinity of the first stator blade 7 viewed from the axial direction upper side. Note that FIG. 3A corresponds to a portion surrounded by a dot and dash line in FIG. 1. Furthermore, in FIG. 3A, in order to facilitate the understanding of the configuration, illustration of the blower case 32 is omitted. FIG. 3B illustrates a cross section structure taken along a dot and dash line A-A in FIG. 3A. FIG. 3C illustrates a cross section structure taken along a dot and dash line B-B in FIG. 3A.

The first stator blade 7 includes a front wall portion 71 and the rear wall portion 72. The front wall portion 71 is disposed in the forward rotation direction end portion of the first stator blade 7. The rear wall portion 72 is disposed in the backward rotation direction end portion of the first stator blade 7. The axial direction of each of the front wall portion 71 and the rear wall portion 72 is at least the longitudinal direction.

Furthermore, the stator blade recess portion 7 a is provided between the rotation direction front wall portion 71 and the rotation direction rear wall portion 72 of the first stator blade 7 in the upper portion of the first stator blade 7. As illustrated in FIG. 3A, in the present embodiment, the stator blade recess portion 7 a is recessed in the upper portion of the first stator blade 7 from the forward rotation direction end portion towards the axial direction lower side. Furthermore, when viewed in the radial direction, the communication hole 3 a is provided between the front wall portion 71 and the rear wall portion 72 in the circumferential direction. With the above configuration, a portion of the airflow flowing between the first stator blade 7 and the stator blade 33 that is adjacent thereto in the forward rotation direction FRD flows into a portion between the front wall portion 71 and the rear wall portion 72. Accordingly, the portion of the airflow can flow into the motor housing 31 in a smooth manner through the communication hole 3 a.

Note that as the bore of the communication hole 3 a becomes larger, the airflow flowing in through the stator blade recess portion 7 a flows more easily into the motor housing 31. Accordingly, a circumferential direction width W1 of the first stator blade 7 is, among the plurality of stator blades 33, desirably, larger than the circumferential direction widths W2 of the second stator blades 331 other than the first stator blade 7. With the above configuration, the width of the communication hole 3 a in the circumferential direction can be enlarged. Accordingly, the cooling effect of the motor 110 is improved.

In the upper portion of the first stator blade 7, a forward rotation direction lateral surface 71 a of the front wall portion 71 is a curved surface that extends downwards in the axial direction as the lateral surface 71 a extends in the forward rotation direction FRD. The forward rotation direction lateral surface 71 a protrudes in the forward rotation direction FRD and towards the axial direction upper side. With such a configuration, the airflow flowing between the first stator blade 7 and the stator blade 33 adjacent to the first stator blade 7 in the rotation direction can be guided smoothly towards the axial direction lower side and in the forward rotation direction FRD. Accordingly, the air blowing efficiency of the blowing device 100 can be improved.

In the upper portion of the first stator blade 7, a backward rotation direction lateral surface 71 b of the front wall portion 71 desirably extends in the axial direction as in the present embodiment. However, the backward rotation direction lateral surface 71 b of the front wall portion 71 may be a curved surface that extends towards the circumferential direction as the lateral surface 71 b extends towards the axial direction upper side. In a case in which the backward rotation direction lateral surface 71 b of the front wall portion 71 extends in the axial direction, when the first stator blade 7 that is molded using a metal mold is released from the metal mold, the metal mold can be taken out upwards or downwards, that is, the metal mold can be taken out in the axial direction. Accordingly, the first stator blade 7 can be molded without using a complex-shaped metal mold.

In the upper portion of the first stator blade 7, a backward rotation direction lateral surface 72 a of the rear wall portion 72 is a curved surface that extends downwards in the axial direction as the lateral surface 72 a extends in the forward rotation direction FRD. The backward rotation direction lateral surface 72 a is recessed in the forward rotation direction FRD and towards the axial direction upper side. With such a configuration, the airflow flowing between the first stator blade 7 and the stator blade 33 adjacent to the first stator blade 7 in the backward rotation direction BRD can be guided smoothly in the forward rotation direction FRD and towards the axial direction lower side. Accordingly, the air blowing efficiency of the blowing device 100 can be improved.

Furthermore, an upper end of the rear wall portion 72 is positioned on the forward rotation direction FRD side with respect to the stator blade 33 adjacent to the first stator blade 7 in the backward rotation direction BRD. With such a configuration, when the first stator blade 7 that is molded using a metal mold is released from the metal mold, the metal mold can be taken out upwards or downwards, that is, the metal mold can be taken out in the axial direction. Accordingly, the first stator blade 7 can be molded without using a complex-shaped metal mold.

The first stator blade 7 further includes a connection wall portion 73. In the present embodiment, the connection wall portion 73 is a lower portion of the first stator blade 7. In more detail, the connection wall portion 73 connects a lower end portion of the front wall portion 71 and a lower end portion of the rear wall portion 72 to each other. In other words, the front wall portion 71 protrudes and extends towards the axial direction upper side from the forward rotation direction end portion at the upper end of the connection wall portion 73. The rear wall portion 72 protrudes and extends towards the axial direction upper side from the backward rotation direction end portion at the upper end of the connection wall portion 73. In the upper end portion of the first stator blade 7, as the rear wall portion 72 extends towards the axial direction upper side, the rear wall portion 72 extends towards the backward rotation direction BRD. With such a configuration, the entire airflow that flows into a portion between the front wall portion 71 and the rear wall portion 72 can be distributed through the communication hole 3 a.

In the present embodiment, an upper surface 73 a of the connection wall portion 73 extends towards the axial direction lower side as the upper surface 73 a extends towards the radial direction inner side. Furthermore, the upper surface 73 a of the connection wall portion 73 is also a bottom surface of the stator blade recess portion 7 a. Accordingly, in other words, the bottom surface of the stator blade recess portion 7 a has a shape that extends towards the axial direction lower side as the bottom surface extends towards the radial direction inner side. Note that the upper surface 73 a may be an inclined surface having a planer shape, or may be a curved surface that protrudes towards the axial direction upper side and the radial direction inner side. Alternatively, the upper surface 73 a may be a curved surface recessed towards the axial direction lower side and the radial direction outer side. With such a configuration, the airflow flowing into the portion between the front wall portion 71 and the rear wall portion 72 can be distributed along the upper surface 73 a of the connection wall portion 73 and to the communication hole 3 a in a smooth manner.

Note that by inclining or curving the inner lateral surface of the communication hole 3 a, the airflow can be made the flow in a smoother manner. Accordingly, as illustrated in FIG. 3C, circumferential direction lateral surfaces of the communication hole 3 a, desirably, extend in the forward rotation direction FRD as the circumferential direction lateral surfaces extend towards the radial direction inner side, for example. Note that in the present embodiment, an inner lateral surface 30 a of the communication hole 3 a in the forward rotation direction and an inner lateral surface 30 b of the communication hole 3 a in the backward rotation direction are both shaped so as to extend in the forward rotation direction FRD as the inner lateral surfaces extend towards the radial direction inner side. The inner lateral surface 30 a of the communication hole 3 a in the forward rotation direction is one of the circumferential direction lateral surfaces of the communication hole 3 a, and an edge portion of inner lateral surface 30 a of the communication hole 3 a in the forward rotation direction is the backward rotation direction lateral surface of the motor housing 31. The inner lateral surface 30 b of the communication hole 3 a in the backward rotation direction is the other circumferential direction lateral surface of the communication hole 3 a, and an edge portion of the inner lateral surface 30 b of the communication hole 3 a in the backward rotation direction is the forward rotation direction lateral surface of the motor housing 31. However, not limited to the example of the present embodiment, it is only sufficient that at least either one of the inner lateral surface 30 a of the communication hole 3 a in the forward rotation direction and the inner lateral surface 30 b of the communication hole 3 a in the backward rotation direction has the shape described above. With such a configuration, the airflow that flows into the portion between the front wall portion 71 and the rear wall portion 72 can be distributed through the communication hole 3 a in a smooth manner. Accordingly, a decrease in the air blowing efficiency of the motor 110 caused by a portion of the airflow, which is flowing between the first stator blade 7 and another stator blade 33, flowing between the front wall portion 71 and the rear wall portion 72 can be suppressed.

Furthermore, while the inner lateral surfaces 30 a and 30 b may each be a curved surface protruding towards the radial direction inner side and in the backward rotation direction or a planer-shaped inclined surface, as illustrated in FIG. 3C, desirably, the inner lateral surfaces 30 a and 30 b are each a curved surface protruding towards the radial direction outer side and in the forward rotation direction. With the above configuration, the airflow can flow further smoothly through the communication hole 3 a.

Furthermore, as illustrated in FIG. 3B, desirably, the inner surfaces of the communication hole 3 a in the axial direction extend towards the axial direction lower side as the inner surface extends towards the radial direction inner side, for example. Note that in the present embodiment, an inner surface 30 c of the communication hole 3 a on the axial direction upper side and an inner surface 30 d of the communication hole 3 a on the axial direction lower side are both shaped so as to extend towards the axial direction lower side as the inner surfaces extend towards the radial direction inner side. The inner surface 30 c of the communication hole 3 a on the axial direction upper side is one of the inner surfaces of the communication hole 3 a in the axial direction, and an edge portion of the inner surface 30 c of the communication hole 3 a on the axial direction upper side is an upper surface of the motor housing 31. The inner surface 30 d of the communication hole 3 a on the axial direction lower side is the other inner surface of the communication hole 3 a in the axial direction, and an edge portion of the inner surface 30 d of the communication hole 3 a on the axial direction lower side is a lower surface of the motor housing 31. However, not limited to the example of the present embodiment, it is only sufficient that at least either one of the lower surface of the motor housing 31 at the upper edge portion of the communication hole 3 a in the axial direction and the upper surface of the motor housing 31 at the lower edge portion of the communication hole 3 a in the axial direction extends towards the axial direction lower side as the lower surface or the upper surface extends towards the radial direction inner side. Note that the inner surface 30 c is the lower surface of the motor housing 31 at the axial direction upper edge portion of the communication hole 3 a, and the inner surface 30 d is the upper surface of the motor housing 31 at the axial direction lower edge portion of the communication hole 3 a. The inner surfaces 30 c and 30 d may each be a planer-shaped inclined surface or may be a curved surface that protrudes or that is recessed in the axial direction and in the radial direction. With such a configuration, the airflow that flows into the communication hole 3 a from between the front wall portion 71 and the rear wall portion 72 can be distributed into the motor housing 31 in a smooth manner. Accordingly, a decrease in the air blowing efficiency of the motor 110 caused by a portion of the airflow, which is flowing in the stator blade recess portion 7 a, flowing between the front wall portion 71 and the rear wall portion 72 can be suppressed.

First to third modifications of the embodiment will be described next.

A configuration different from that of the embodiment described above will be described in the first modification. Furthermore, components similar to those of the embodiment may be denoted with the same reference numerals and description thereof may be omitted.

FIG. 4 is an enlarged view illustrating the first stator blade 7 according to the first modification. Note that FIG. 4 corresponds to a portion surrounded by the dot and dash line in FIG. 1. Furthermore, in FIG. 4, in order to facilitate the understanding of the configuration, illustration of the blower case 32 is omitted.

As illustrated in FIG. 4, in the upper portion of the first stator blade 7 in the first modification, an upper end of the front wall portion 71 is on the axial direction upper side with respect to the upper end of the rear wall portion 72. Accordingly, the stator blade recess portion 7 a is recessed towards the axial direction lower side from a backward rotation direction end portion of the first stator blade 7 and along the shape of the upper portion of the first stator blade 7.

Furthermore, in the upper portion of the first stator blade 7, the backward rotation direction lateral surface 71 b of the front wall portion 71 is a curved surface that extends downwards in the axial direction as the lateral surface 71 b extends in the forward rotation direction FRD. The backward rotation direction lateral surface 71 b is recessed in the forward rotation direction FRD and towards the axial direction upper side.

Even with such a configuration, a portion of the airflow flowing between the first stator blade 7 and the stator blade 33 adjacent to the first stator blade 7 in the backward rotation direction BRD can be distributed in a smooth manner between the front wall portion 71 and the rear wall portion 72.

A configuration different from that of the first modification described above will be described in the second modification. Furthermore, components similar to those of the embodiment and the first modification described above may be denoted with the same reference numerals and description thereof may be omitted. Note that the configuration of the second modification described below can also be applied to the embodiment described above.

FIG. 5 is an enlarged view illustrating the first stator blade 7 according to the second modification. Note that FIG. 5 corresponds to a portion surrounded by the dot and dash line in FIG. 1. Furthermore, in FIG. 5, in order to facilitate the understanding of the configuration, illustration of the blower case 32 is omitted.

As illustrated in FIG. 5, in the second modification, the front wall portion 71 is a member that is different from the rear wall portion 72 and the connection wall portion 73. The rear wall portion 72 is a portion of a member that includes the connection wall portion 73. In other words, the lower end portion of the front wall portion 71 is in contact with an upper end portion of the connection wall portion 73 at the forward rotation direction end portion of the first stator blade 7. The rear wall portion 72 protrudes towards the axial direction upper side from the backward rotation direction end portion at the upper end of the connection wall portion 73, and as the rear wall portion 72 extends towards the axial direction upper side, the rear wall portion 72 extends towards the backward rotation direction BRD. Note that not limited to the example illustrated in FIG. 5, the front wall portion 71 may be a portion of a member that includes the connection wall portion 73, and the rear wall portion 72 may be a member that is different from the front wall portion 71 and the connection wall portion 73.

The front wall portion 71 is a portion of a member that includes either one of the motor housing 31 and the blower case 32. In other words, a first end portion of the front wall portion 71 in the radial direction is connected to either one of the motor housing 31 and the blower case 32. A second end portion of the front wall portion 71 in the radial direction is in contact with the other one of the motor housing 31 and the blower case 32. In other words, the front wall portion 71 protrudes in the radial direction from a radial direction lateral surface of either one of the motor housing 31 and the blower case 32 at a portion between the motor housing 31 and the blower case 32. A front end of the front wall portion 71 in the radial direction is in contact with a radial direction lateral surface of the other one of the motor housing 31 and the blower case 32.

Furthermore, the rear wall portion 72 is a portion of a member that includes the other one of the motor housing 31 and the blower case 32. In other words, a first end portion of the rear wall portion 72 in the radial direction is in contact with either one of the motor housing 31 and the blower case 32. A second end portion of the rear wall portion 72 in the radial direction is connected to the other one of the motor housing 31 and the blower case 32. In other words, the rear wall portion 72 protrudes in the radial direction from a radial direction lateral surface of the other one of the motor housing 31 and the blower case 32 at a portion between the motor housing 31 and the blower case 32. A front end of the rear wall portion 72 in the radial direction is in contact with a radial direction lateral surface of either one of the motor housing 31 and the blower case 32.

Note that in the third modification, the connection wall portion 73 is, similar to the rear wall portion 72, a portion of a member that includes the other one of the motor housing 31 and the blower case 32. However, in a case in which the connection wall portion 73 is a portion of a member that includes the front wall portion 71, similar to the front wall portion 71, the connection wall portion 73 is a portion of a member that includes either one of the motor housing 31 and the blower case 32.

With such a configuration, when separating the front wall portion 71 molded together with either one of the motor housing 31 and the blower case 32 from a metal mold, the metal mold can be taken out upwards or downwards, that is, the metal mold can be taken out in the axial direction. Furthermore, when separating the rear wall portion 72 molded together with the other one of the motor housing 31 and the blower case 32 from a metal mold, the metal mold can be taken out upwards or downwards, that is, the metal mold can be taken out in the axial direction. Accordingly, as illustrated in FIG. 5, even when the first stator blade 7 has a complex shape in which the front wall portion 71 and the rear wall portion 72 overlap each other in the axial direction, for example, the first stator blade 7 can be molded without using a complex-shaped metal mold.

A configuration different from that of the second modification described above will be described in the third modification. Furthermore, components similar to those of the embodiment and the second modification described above may be denoted with the same reference numerals and description thereof may be omitted. Note that the configuration of the third modification described below can also be used in the embodiment described above.

FIG. 6 is an enlarged view illustrating the first stator blade 7 according to the third modification. Note that FIG. 6 corresponds to a portion surrounded by the dot and dash line in FIG. 1. Furthermore, in FIG. 6, in order to facilitate the understanding of the configuration, illustration of the blower case 32 is omitted.

As illustrated in FIG. 6, in the third modification, the motor housing 31 includes an upper motor housing 31 a and a lower motor housing 31 b. The lower motor housing 31 b is attached below the upper motor housing 31 a in the axial direction. Note that the upper motor housing 31 a may be a member different from the blower case 32 or may be a portion of a member that includes the blower case 32. Meanwhile, the lower motor housing 31 b is a member different from the blower case 32. Alternatively, in a case in which the blower case 32 is formed of a plurality of members that can be assembled together, the upper motor housing 31 a may be a portion of a member that includes the blower case 32 and the lower motor housing 31 b may be a portion of a member that includes another member of the blower case 32.

In FIG. 6, while the front wall portion 71 is a portion of a member that includes the upper motor housing 31 a, the front wall portion 71 is a member different from the lower motor housing 31 b. However, not limited to the example in FIG. 6, the front wall portion 71 may be a member different from the upper motor housing 31 a, and may be a portion of a member that includes the lower motor housing 31 b. In other words, it is only sufficient that the front wall portion 71 is a portion of a member that includes either one of the upper motor housing 31 a and the lower motor housing 31 b.

In FIG. 6, the rear wall portion 72 is a member different from the upper motor housing 31 a; however, the rear wall portion 72 is a portion of a member that includes the lower motor housing 31 b. However, not limited to the example in FIG. 6, the rear wall portion 72 may be a portion of a member that includes the upper motor housing 31 a and may be a member that is different from the lower motor housing 31 b. In other words, it is only sufficient that the rear wall portion 72 is a portion of a member that includes the other one of the upper motor housing 31 a and the lower motor housing 31 b.

Note that in the third modification, the connection wall portion 73 is, similar to the rear wall portion 72, a portion of a member that includes the lower motor housing 31 b. However, in a case in which the connection wall portion 73 is a portion of a member that includes the front wall portion 71, similar to the front wall portion 71, the connection wall portion 73 is a portion of a member that includes the upper motor housing 31 a.

With such a configuration, when separating the front wall portion 71 molded together with either one of the upper motor housing 31 a and the lower motor housing 31 b from a metal mold, the metal mold can be taken out upwards or downwards, that is, the metal mold can be taken out in the axial direction. Furthermore, when separating the connection wall portion 73 molded together with the other one of the upper motor housing 31 a and the lower motor housing 31 b from a metal mold, the metal mold can be taken out upwards or downwards, that is, the metal mold can be taken out in the axial direction. Accordingly, as illustrated in FIG. 6, even when the first stator blade 7 has a complex shape in which the front wall portion 71 and the rear wall portion 72 overlap each other in the axial direction, for example, the first stator blade 7 can be molded together with the upper motor housing 31 a and the lower motor housing 31 b without using a complex-shaped metal mold.

An example in which the blowing device 100 described above is mounted in a vacuum cleaner 200 will be described next. FIG. 7 is a perspective view illustrating a configuration of the vacuum cleaner 200 in which the blowing device 100 is mounted. The vacuum cleaner 200 includes the blowing device 100. In more detail, the vacuum cleaner 200 includes the blowing device 100, a nozzle 210, and a main body 220. The blowing device 100 is mounted in the main body 220. A suction brush (not shown) is attached to an intake portion 211 of the nozzle 210. The main body 220 includes a dust chamber 221 connected to the nozzle 210, a housing chamber 222 in which the blowing device 100 is housed, and an exhaust space 223 connected to a plurality of exhaust ports (not shown). An opening portion of the blowing device 100 is connected to the dust chamber 221 with a dust collection filter (not shown) interposed therebetween. In other words, a flow passage of the air suctioned by the blowing device 100 is connected from the intake portion 211, through the nozzle 210 and the dust chamber 221, and to the opening portion of the blowing device 100 in the above order. The housing chamber 222 is connected to the exhaust space 223. The airflow sent out with the blowing device 100 is discharged to the outside of the main body 220 through the exhaust space 223 and through the exhaust ports. With the above, the vacuum cleaner 200 including the blowing device 100 capable of effectively suppressing the air blowing efficiency from decreasing can be attained.

Note that the blowing device 100 in FIG. 7 is mounted in a stick-type vacuum cleaner 200; however, not limited to the example of the present embodiment described above, the blowing device 100 may be mounted in a vacuum cleaner of another type. For example, the vacuum cleaner 200 may be, for example, a vacuum cleaner of a canister type or of a handy type.

The present disclosure is suitable for an apparatus that suctions or sends out gas and that is required to have a high static pressure. The present disclosure can be used in blowing devices other than a vacuum cleaner (see FIG. 7) such as an electric fan or a ventilation fan and, further, can be used in electrical appliances for other purposes such as a drying device.

Features of the above-described preferred embodiments and the modifications thereof may be combined appropriately as long as no conflict arises.

While preferred embodiments of the present disclosure have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present disclosure. The scope of the present disclosure, therefore, is to be determined solely by the following claims. 

What is claimed is:
 1. A blowing device comprising: a motor including a rotor rotatable about a central axis extending in an up-down direction; an impeller that is fixed to the rotor and that is rotatable together with the rotor; a motor housing disposed on a radial direction outer side with respect to the motor; a blower case disposed on the radial direction outer side with respect to the motor housing; and a plurality of stator blades arranged in a circumferential direction and between the motor housing and the blower case; wherein the plurality of stator blades include at least a single first stator blade provided with a stator blade recess portion recessed in a surface of a stator blade of the plurality of stator blades; a communication hole that connects an internal portion and an external portion of the motor housing to each other is provided in the motor housing; the communication hole is provided between a forward rotation direction end portion and a backward rotation direction end portion in the first stator blade and is in communication with the stator blade recess portion; the first stator blade includes: a front wall portion disposed in the forward rotation direction end portion; and a rear wall portion disposed in the backward rotation direction end portion; an axial direction of each of the front wall portion and the rear wall portion is a longitudinal direction; the communication hole is provided in the circumferential direction and between the front wall portion and the rear wall portion; the first stator blade further includes a connection wall portion that connects a lower end portion of the front wall portion and a lower end portion of the rear wall portion to each other; and an upper surface of the connection wall portion extends towards an axial direction lower side as the upper surface extends towards a radial direction inner side.
 2. The blowing device according to claim 1, wherein in an upper portion of the first stator blade, a backward rotation direction lateral surface of the rear wall portion is a curved surface that extends towards the axial direction lower side as the backward rotation direction lateral surface extends in the forward rotation direction, and is recessed in the forward rotation direction and towards an axial direction upper side.
 3. The blowing device according to claim 1, wherein in an upper portion of the first stator blade, a forward rotation direction lateral surface of the front wall portion is a curved surface that extends towards the axial direction lower side as the forward rotation direction lateral surface extends in the forward rotation direction, and protrudes in the forward rotation direction and towards an axial direction upper side.
 4. The blowing device according to claim 1, wherein in an upper portion of the first stator blade, a backward rotation direction lateral surface of the front wall portion extends in the axial direction.
 5. The blowing device according to claim 1, wherein an upper end of the front wall portion is on an axial direction upper side with respect to an upper end of the rear wall portion.
 6. The blowing device according to claim 5, wherein in an upper portion of the first stator blade, a backward rotation direction lateral surface of the front wall portion is a curved surface that extends towards the axial direction lower side as the backward rotation direction lateral surface extends in the forward rotation direction, and is recessed in the forward rotation direction and towards an axial direction upper side.
 7. The blowing device according to claim 1, wherein the front wall portion is a portion of a member that includes either one of the motor housing and the blower case; and the rear wall portion is a portion of a member that includes the other one of the motor housing and the blower case.
 8. The blowing device according to claim 1, wherein the motor housing includes: an upper motor housing; and a lower motor housing attached below the upper motor housing in the axial direction; the front wall portion is a portion of a member that includes either one of the upper motor housing and the lower motor housing; and the rear wall portion is a portion of a member that includes the other one of the upper motor housing and the lower motor housing.
 9. The blowing device according to claim 1, wherein a circumferential direction width of the first stator blade is larger than a circumferential direction width of a second stator blade, the second stator blade being a stator blade other than the first stator blade among the plurality of stator blades.
 10. The blowing device according to claim 1, wherein a circumferential direction lateral surface of the communication hole extends towards the forward rotation direction as the circumferential direction lateral surface extends towards the radial direction inner side.
 11. The blowing device according to claim 1, wherein at least either one of a lower surface of the motor housing at an axial direction upper edge portion of the communication hole and an upper surface of the motor housing at an axial direction lower edge portion of the communication hole extends towards the axial direction lower side as the lower surface or the upper surface extends towards the radial direction inner side.
 12. The blowing device according to claim 1, wherein the communication hole is provided in a plural number and at equal distances in the circumferential direction.
 13. A vacuum cleaner comprising the blowing device according to claim
 1. 